Firefighters and Kawhia locals came to the rescue of a rural Waikato policeman last night when he was knocked to the ground and attacked by at least five offenders, police say.

The policeman had been set upon by at least five people, who were kicking him as he coiled up in pain on the Kawhia wharf, as about 80 members of the public watched on, inspector Rob Lindsay said.

The group took his taser, his radio and his pistol and were only stopped when local firefighters and the public stepped in to intervene. If they hadn't, the outcome could have been much worse, Lindsay said.

Although the officer had called for back-up, his closest colleagues were 70km away in Ngahinapouri and couldn't make it to the scene in time to put a quick stop to the attack, which left him with serious bruising and grazing to his face, arms and body.

"He has some severe bruising around his body and his head to the extent that this morning he is having trouble walking," Lindsay said. The sole-charge constable is recovering with family outside of the small coastal town.

Police have painted a detailed picture of the events leading up to the attack and are appealing to the Kawhia community to help identify who was responsible.

Three people, including a father and son, appeared in court today facing charges of aggravated assault and assault with intent to injure, but at least two more offenders remain at large.

The policeman had located a 19-year-old man, known to be violent towards police and facing outstanding arrest warrants, shortly before 6pm last night. A stand-off between the two men ensued and a relative of the 19-year-old was subsequently called to help de-escalate the situation, but he ended up setting on the policeman instead.

The policeman used pepper spray on the offenders, which had little affect, and then presented his taser, which was grabbed by one of them.

The officer was able to break free and deploy his taser on the main offender, who had rushed at him, police said. He was handcuffing the man when he was struck from behind and knocked to the ground.

"From there the officer has been kicked on the ground by a group of what we estimate to be five people and he has crawled into a ball and activated his Officer Safety Alarm," inspector Rob Lindsay said.

"Cambridge staff at that time were at Ngahinapouri and were dispatched to go to the officer's assistance, unfortunately even with the best driver's skills it is still some distance to travel."

Aware of the situation and the policeman's isolation, his colleagues called the local fire brigade, who arrived at the wharf to find the officer on the ground being attacked.

The policeman's taser, pistol and radio were all taken from him.

"Fortunately for all concerned a member of the public recovered the officer's pistol and took it to the firefighters who secured the weapon," Lindsay said.

"A short time later police reinforcements arrived from across the district and the 19-year-old man, his 49-year-old father and a 21-year-old male associate were arrested without further incident."

The injured policeman was examined by ambulance staff and a local doctor and was to undergo further assessments today.

"The officer has asked me to acknowledge on his behalf the bravery shown by the firefighters and members of the public who's direct action prevented what could have been a far more serious outcome," Lindsay said. "It is these people who are the true spirit of the Kawhia community."

It was the fifth attack on Waikato police over the holiday period.

"Here we have a uniformed member of a small community trying to protect that same community," Lindsay said.

"With this being the fifth attack on officers as they try and assist people in need the message needs to be clear that such attacks on our staff will not be tolerated."

Anyone with information is asked to contact police on 07 858 6200 or call Crimestoppers anonymously on 0800 555111